Soluble coffee beverage products of the instant "cappuccino" type are well known and are commercially available. Usually these products are a dry mix of a soluble coffee powder and a soluble whitener powder. The soluble whitener powder contains pockets of gas which, upon dissolution of the powder, produce foam. Therefore, upon the addition of water (usually hot), a whitened coffee beverage, which has a foam on its upper surface, is formed; the beverage resembling, to a greater or lesser extent, traditional Italian cappuccino.
Of the two main components of the soluble coffee beverage product, the soluble whitener powder has shown to be the most problematic. In order to produce an acceptable beverage, little or no lumps should form upon dissolution. Unfortunately, dairy proteins are susceptible to flocculation in the presence of raised temperatures and acidic conditions; both of which are present upon dissolution of the soluble beverage powder. However, flocculation is one of the causes of the formation of lumps. Further, to closely resemble a traditional Italian cappuccino, a white, stable foam should form on the surface of the beverage. However, quite often the foam produced by soluble "cappuccino" powders is not white; instead it has a brownish color.
A soluble whitener powder of excellent stability and ability to foam is described in U.S. Pat. No. 4,746,527. The soluble whitener powder described in this patent is made up of fats, lactic proteins, lactose and a stabilizer system. The ratio of lactic proteins to lactose must be in the range of 1:3.5 to 1:5 and the stabilizer system consists of a citrate salt and a phosphate salt. Carbohydrates other than lactose may also be present. To ensure foaming, the soluble whitener powder is subjected to gassing during spray drying so that the soluble whitener powder contains gas.
The soluble whitener powder described in this patent has been extremely successful commercially in that it produces an excellent, stable foam. However the foam produced may have a slight brownish color and consequently may not be as white as the foams of traditional Italian cappuccino.
Another soluble whitener powder intended for "cappuccino" products is described in European patent 0458310. The soluble whitener powder described in this patent is made up of dry skimmed milk solids, lactose, fats, caseinates and alkali phosphate. These components are mixed with water, pasteurized, homogenized, gassed with carbon dioxide or nitrogen and spray-dried. The powder is described to produce a good foam. It is also mentioned that, due to the use of skimmed milk concentrates, a whiter foam is produced. However, since hot water is added to a dry mix of the soluble coffee powder and the soluble whitener powder to form the beverage, some coffee solids will color the milk proteins forming the foam and give them a brown color. Consequently the beverage produced will have a brownish foam. Also flocculation of the dairy proteins and the formation of lumps may occur.
Therefore there is still a need for a soluble coffee beverage product which provides a stable, white foam upon a beverage formed by the addition of water.